Rotary and/or linear actuator system for controlling operation of an associated tool

ABSTRACT

A rotary-linear system is configured to operate an associated tool. The system includes a rotary-linear actuator having first and second portions that can move linearly and/or rotationally relative to each other, such as about a central axis extending through the actuator. An elongated drive rod extends axially through at least a portion of the actuator, which is operative to rotate about a longitudinal axis thereof generally independently of the actuator. While the rotation of the drive rod can be independent of movement of the actuator, such rotation can be controlled based on the position and/or movement of the actuator. An end of the drive rod near a distal end of the actuator is operative to actuate an associated tool, such as can be mounted at a distal end of the actuator.

TECHNICAL FIELD

The present invention relates to motors and, more particularly, tolinear and/or rotary system operative to control operation of anassociated tool.

BACKGROUND OF THE INVENTION

Various kinds of actuators are employed in manufacturing differentproducts. The type of actuator usually is selected based on designtolerances and precision required to manufacture the products with suchtolerances. For example, linear actuators are used for numerous taskswhere a linear movement or application of a generally linear force isdesired. Rotary actuators are employed to rotate or spin objects. Insome circumstances, it is desirable to combine linear and rotaryactuators to provide both linear and rotary movement of an object.

Some typical manufacturing environments that employ one or moredifferent types of robotic actuators include semiconductor manufacturingprocesses (e.g., pick and place systems), printed circuit boardfabrication (e.g., the placement and connection of circuit componentsonto the circuit board), etc. Often times, the robotic actuators areprogrammed and/or configured to move one or more tools between one ormore locations at which the tools are to operate on a work piece.

In order to remain competitive in today's global economy, manufacturersrequire actuators that can achieve greater precision and speed so as toincrease production rates. Thus, it is desirable to provide an actuatorcapable of quickly and accurately positioning a tool in associatedmanufacturing processes.

SUMMARY

The following presents a simplified summary of the invention in order toprovide a basic understanding of some aspects of the invention. Thissummary is not an extensive overview of the invention. It is intended toneither identify key or critical elements of the invention nor delineatethe scope of the invention. Its sole purpose is to present some conceptsof the invention in a simplified form as a prelude to the more detaileddescription that is presented later.

One aspect of the present invention provides an actuator system foroperating a tool. The actuator system includes a housing and anelongated plunger mounted within the housing for rotary and linearmovement relative to the housing and a central axis extendinglongitudinally through the plunger. An elongated drive rod extendswithin at least a portion of the rotary linear actuator substantiallyparallel to the central axis. Part of the drive rod is connected withthe plunger so that the drive rod moves linearly commensurate with thelinear movement of the plunger. The drive rod further is capable ofindependent rotary movement relative to plunger. In a particular aspectof the present invention, a drive system is operatively connected torotate the drive rod about its longitudinal axis independently ofmovement of the plunger.

In accordance with another aspect of the present invention, a toolassembly can be attached, either removably attached or permanentlyfixed, to the plunger so that rotation of the drive rod relative to theplunger activates the tool assembly. For example, the tool assembly canbe glue dispenser operative to dispense a desired amount of an adhesivematerial in response to rotation of the drive rod.

Another aspect of the present invention provides a method forcontrolling a tool system. For example, the tool system includes arotary-linear actuator that can provide linear and rotary movement of aplunger relative to a housing. A drive rod is associated with theactuator to move linearly with plunger and further can rotateindependently of relative to the plunger. At least one of rotary andlinear position of the plunger is adjusted to a desired position. Afterthe plunger is at a desired position, the drive rod can be rotatedindependently of plunger so as to activate an associated tool.

To the accomplishment of the foregoing and related ends, certainillustrative aspects of the invention are described herein in connectionwith the following description and the annexed drawings. These aspectsare indicative, however, of but a few of the various ways in which theprinciples of the invention may be employed and the present invention isintended to include all such aspects and their equivalents. Otheradvantages and novel features of the invention will become apparent fromthe following detailed description of the invention when considered inconjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial side sectional view of a rotary-linear tool systemin accordance with an aspect of the present invention, illustrating thetool in a first condition.

FIG. 2 is a partial side sectional view of a rotary-linear tool systemin accordance with an aspect of the present invention, illustrating thetool in a second condition.

FIG. 3 is a cross sectional view of part of a rotary-linear tool systemtaken along line 3—3 of FIG. 1.

FIG. 4 is a sectional view of a rotary linear tool system in accordancewith an aspect of the present invention.

FIG. 5 is a partial side sectional view of a rotary-linear tool systemin accordance with an aspect of the present invention, illustrating atool assembly in a detached condition.

FIG. 6 is a functional block diagram of a rotary-linear tool system inaccordance with an aspect of the present invention.

FIG. 7 is a flow diagram illustrating a methodology for operating arotary-linear tool system in accordance with an aspect of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a rotary-linear system configured tooperate an associated tool. The system includes a rotary-linear actuatorhaving first and second portions that can move linearly and/orrotationally relative to each other, such as about a central axisextending through the actuator. A drive rod extends axially through atleast a portion of the actuator, which is operative to rotate about alongitudinal axis thereof independently relative to the actuator. Whilethe rotation of the drive rod can be independent of movement of theactuator, such rotation can be controlled based on the position and/ormovement of the actuator. The drive rod can be operatively associatedwith a tool, so that movement of the drive rod is transferred to drive atool. Thus, by controlling rotation of the drive rod, the operation ofthe associated tool also can be controlled.

FIGS. 1 and 2 illustrate a high-precision tool system 10 in accordancewith an aspect of the present invention. The tool system 10 includes arotary-linear actuator 12 and a tool assembly 14 operatively associatedwith the actuator. The actuator 12 includes an inner portion (orplunger) 16 that is moveable relative to a housing 18. The housing 18has an outer sidewall portion 20 that extends between spaced apart ends22 and 24. The plunger 16 has a generally cylindrical sidewall portion26 that extends between spaced apart end portions 28 and 30. Theproximal end 28 of the plunger 16 thus can travel between the ends 22and 24 of the housing 18 according to relative movement between theplunger and housing. In particular, the plunger 16 can move rotationallyabout and/or linearly along an axis 32 that extends through the ends 28and 30 thereof. Appropriate bearings (low friction or air bearings) orother guide mechanisms (not an shown) facilitate desired relative motionbetween the plunger 18 and housing 16.

The actuator 12 further includes an arrangement of magnets 34 andwindings 36. The magnets and windings are operatively associated withthe housing 18 and the plunger 16 to enable desired linear and rotarymotion therebetween. It is to be understood and appreciated that themagnets can be mounted to one of an inner portion of the housing 18 andan exterior 38 of the plunger sidewall portion 26 and the windings 36can be mounted to a different one of the respective exterior of theplunger sidewall portion and inner portion of the housing 18.

In the example illustrated in FIGS. 1 and 2, the magnets 34 are disposedon the exterior portion 38 of the plunger 16, such that adjacent magnetshave alternating polarities. A portion of the magnets 34 are oriented sothat their north poles point radially outward and another portion of themagnets are oriented so that their north poles point radially inward.For example, the magnets 34 are arranged along the exterior portion 38,such that a circumferential array of magnets that circumscribe a portionof the plunger 16. The magnets 34 further can be arranged so onemagnetic polarity alternate with adjacent axially displaced arrays ofmagnets having an opposite polarity and axially extending columns of onepolarity alternate with columns of opposite polarity (e.g., a circularcylindrical sidewall having a substantially checker-board like array ofmagnets).

U.S. Pat. No. 6,215,206 discloses examples of possible magnet andwinding configurations for a rotary-linear actuator, all of which couldbe utilized in accordance with an aspect of the present invention. Forexample, the magnets 34 could be round and arranged in a pattern or theycould be diamond shaped and arranged in a desired pattern, such thatadjacent magnets have different relative magnetic polarity. Thealternative arrangements of magnets have different torquecharacteristics that may be desirable for a rotary-linear actuator inspecific applications. Those skilled in the art will further understandand appreciate various configurations of magnets and associated windings36 that could be employed to facilitate rotational and linear movementof the plunger 16 relative to the housing 18, which are equallyapplicable to the tool system 10 of the present invention.

Referring back to FIGS. 1 and 2, more than one set of windings 36 (e.g.,two or more) are arranged along an interior portion of the housing so asto provide magnetic fields that interact with adjacent magnets and, inturn, effect desired rotational and/or linear movement of the plunger16. For example, the windings 36 include a set of z-axis coils 40, whichextend circumferentially around part of the plunger to facilitaterelative axial movement between the plunger 16 and housing 18. Thez-axis coils 40 are shaped and mounted to the housing 18, such thatcurrent in them generates a magnet field that interacts with the magnetsto move the plunger axially. The windings 36 also include a set ofθ-axis coils 42. The θ-axis coils 42 have longitudinal axes that aresubstantially parallel to the axis 32 of the plunger 16 and facilitaterotational movement between the plunger and the housing 18. The θ-axiscoils 42 are dimensioned and configured so that an energization currentin them generates a magnetic field that interacts with the magnets 34 toprovide a tangential force on the columns of magnets to provide forrelative rotational movement between the plunger 16 and the housing 18.

Each set of the coils 40 42 can be three-phase coils, although othernumber of phases could be utilized to implement such a tool system 10.It is to be understood and appreciated that any configuration windingscan be used in accordance with an aspect of the present invention. Forexample, different numbers of windings could be employed in an actuator12, such as depending on the resolution and size of the actuatorrequired for the application. In addition, the lengths and widths ofcoils and may differ substantially from that shown herein.

A power supply (not shown) provides operating power, which can bedirected to the coils 40 and 42, such as described herein. Any suitablepower supply (e.g., battery, line power) may be utilized to carry outthe present invention. An associated control system and amplifier areoperative to energize the coils 40 and 42 with power to drive theplunger in a desired direction. As a result of the relationship betweenthe magnets and sets of windings, the plunger 16 can be driven linearlyand/or rotationally relative to the housing 18.

The tool system 10 also includes an elongated drive rod 46 that extendsbetween spaced apart ends 48 and 50 thereof substantially parallel tothe actuator axis 32. For example, the drive rod 48 extendssubstantially coaxially through the plunger 16 and the housing 18. Aproximal end 48 of the drive rod 46 is located near the proximal end 22of the housing 18. The housing 18 has an aperture 52 through which thedrive rod 46 can traverse. The aperture 52 is dimensioned and configuredaccording to the cross-sectional dimensions and configuration of thedrive rod 46 (e.g., the aperture approximates the outer diameter of thedrive rod). The distal end 50 of the drive rod is connected to acoupling 54 located near the distal end 30 of the plunger 16. Anintermediate portion 56 of the drive rod 46 extends between the coupling54 and the proximal end 48 of the drive rod.

The coupling 54 can be at a generally fixed axial position relative tothe distal end 30 of the plunger 16. For example, the coupling 54 isformed of a magnetic material (e.g., iron, steel, a suitable alloy,etc.) and is preloaded into engagement with a rigid shelf 58 or otherstructure located near the distal end 30 of the plunger 16. In theexample of FIGS. 1 and 2, the coupling 54 is magnetically preloaded byan arrangement of one or more permanent magnets 60 that attract thecoupling axially toward the shelf 58. The magnet 60 can be configured asone or more generally flat discs permanently magnetized material havinga central aperture 62 extending through the disc. A central aperture 64also extends through the shelf 58 to permit desired attachment of thetool assembly 14 to the coupling 54 through the shelf and the magnet 60.It is to be appreciated that the coupling 54 can move a limited axialdistance relative to the plunger 16, such as within its associatedcoupling chamber 66, if an axial force is applied to tool assembly 14 ina direction opposite to and at a level that exceeds the preloading forceprovided by the magnet 60. Those skilled in the art will understand andappreciated that other mechanisms (e.g., one or more springs, aretaining coupling, motor stops, etc.) can be employed to maintain thecoupling 54 at a desired position of relative to the plunger 16.

In the example illustrated in FIGS. 1 and 2, the coupling chamber 66 isremovably attached to the plunger 16. In particular, the lower end 30 ofthe plunger sidewall 26 is threaded to receive a corresponding threadedend of the coupling chamber 66. That is, the coupling chamber 66,including the coupling 54 and drive rod 56, are removeable relative tothe rotary-linear actuator. The threading of the coupling chamber 66relative to the plunger 16 can be accomplished manually and/or byactivation of the θ-axis coils 42 in a desired manner to rotate theplunger about the axis 32. It is to be understood and appreciated,however, that the coupling chamber 66 could be permanently fixed to theplunger 16.

The coupling 54 also includes an arrangement of one or more bearings 68.In the an illustrated example, a single bearing is fixed to a centralpart of the coupling 54 (coaxial with the axis 32) and is dimensionedand configured to engage part of the tool assembly 14 received in thecoupling 54. The bearing 68 cooperates with the part of tool assembly(e.g., a drive rod thereof) that is received in the coupling 54 so as tofacilitate alignment of the drive rod relative to the coupling 54 aswell as maintain desired spacing between the coupling and the magnet 58.The bearing 68 also can provide a pivot between the drive rod of thetool assembly 14 to permit some relative movement between the toolassembly and the coupling 54. It is to be understood and appreciatedthat other types of bearing arrangements could be utilized in accordancewith an aspect of the present invention.

In view of the preloading of the coupling at the distal end 30 of theplunger, the drive rod 46 can move axially commensurate with axialmovement of the plunger, such as based on actuation of the linear partof the rotary-linear actuator 12. For example, FIG. 1 illustrates theplunger 16 in a first condition, in which the plunger is retracted. Aportion of the drive rod 46 extends axially through the aperture 52 inthe housing 18. As the distal end 30 of the plunger moves axially awayfrom the housing 18, the drive rod 46 also moves commensurate with theplunger. FIG. 2 illustrates the plunger 16 in an extended condition inwhich the distal end 30 of the plunger is spaced a distance from thehousing, such as in response to activation of the linear coils 40 of therotary-linear actuator 12. In the extended motor condition of FIG. 2,the upper end of drive rod 46 has been moved axially through the housing18, such that the proximal end 48 of the drive rod is within theaperture 52. It is to be appreciated that different lengths of driverods from that shown herein could be utilized. Additionally, tofacilitate substantially free axial movement of the drive rod 46 throughthe housing 18, appropriate low friction (or no friction) bearingsand/or bushings could be employed to help guide the drive rod throughthe aperture 52 and housing through which the drive rod traverses.

A drive system 72 is operatively coupled to the drive rod 46 toselectively rotate the drive rod about its longitudinal axis. The drivesystem 72 of FIGS. 1 and 2 is illustrated as including a rotary motor 74operatively coupled to the drive rod 46 by a belt 76. In particular, thebelt 76 extends around a pair of spaced apart axles 78 and 80. One axle78 is connected to and oriented substantially coaxially with therotational axis of the drive motor 74. The other axle 80 is operativelyconnected to and substantially coaxial with the axis of the drive rod46. The axle 80 includes at least part of the aperture 52 through whichpart of the drive rod 46 can traverse, which aperture is dimensioned andconfigured to rotate the drive rod according to rotation of theassociated axle 80. As a result, the drive motor 74 transfers movementfrom the motor axle 78 to the other drive axle 80 through the belt 76,and from the axle 80 to the drive rod 46. While FIGS. 1 and 2 illustratea belt 76 to indirectly drive the drive rod 46, it is to be understoodand appreciated that other types of drive mechanisms (e.g., chain,cables, an arrangement of gears, etc.) also could be employed to rotatethe drive rod in a desired manner.

Referring to the partial cross sectional view of FIG. 3, the drive rod46 has a plurality of elongated ribs (or teeth) 82 along its outersidewall protruding radially outwardly from an inner portion 84. In theexample of FIG. 3, there are four such ribs 82, which provide agenerally +-shaped cross-sectional configuration (e.g., symmetrical ribsor teeth) for the drive rod 46. Elongated channels or grooves 86 extendbetween each adjacent pair of ribs. The channels 86 receive mating teeth(or other protrusions) 88 of a drive gear 90. The operative relationshipbetween the drive gear 90 and the drive rod 46 further permitssubstantially free axial movement of the drive rod relative to the drivegear. Thus, the drive gear 90 is coupled to the axle 80, such thatrotation of the axle is transferred to the drive gear so as to rotatethe drive rod 46 about its longitudinal axis, while still permittingdesired axial movement between the drive rod and gear.

It is to be understood and appreciated that other shapes andconfigurations of drive rod and associated drive gear also could beutilized in accordance with an aspect of the present invention. Forexample, the drive rod 46 could have other cross sectionalconfigurations, such as round, rectangular, hexagonal, octagonal, etc.as well as having any number of teeth (or ribs). The drive gear 90 isconfigured to cooperate with the drive rod 46 to effect its rotation.The drive rod 46 further has a length that is sufficient to maintain itsdesired axial orientation as the plunger 16 moves linearly relative tothe housing 18 between its minimum and maximum positions, such as shownin FIGS. 1 and 2.

Referring back to FIGS. 1 and 2, the tool assembly 14 is operativelyattached at the distal end 30 of the plunger 16. The attachment can bepermanent or it could be a removable connection. In the illustratedexample, the plunger 16 includes a threaded receptacle 94 at the distalend 30 of the plunger operative to receive an appropriately configuredtool assembly 14. The receptacle 94 includes an inner cylindricalsidewall having internal threads 96 for receiving a corresponding partof the tool assembly 14. That is, the tool assembly 14 includes athreaded end portion 98 that is dimensioned and configured for threadinginto the receptacle 94 of the plunger 16. While FIGS. 1 and 2 illustratethe receptacle 94 of the plunger 16 as having female threads and thetool assembly as having male threads, it is to be understood andappreciated that the plunger could have male threads and the toolassembly could have the female threads. Further, those skilled in theart will understand and appreciate various other means (e.g., snapfittings, friction fittings, fasteners, set screws, etc.) could beemployed to removably attach the tool assembly 14 to the actuator 12.Alternatively, in another aspect of the present invention, the toolassembly 14 could be permanently fixed to the plunger 16 by one of theconnector means identified above and/or other types of attachment.

By way of illustration, with the threaded attachment shown in FIGS. 1and 2, activating the actuator 12 in a rotational mode, such as byactivating the θ-axis coils 42 in a desired manner, can facilitate thethreading of the tool assembly 14 to the plunger 16. For example, byrotating the plunger 16 in a first direction while the tool assembly 14is held stationary, the tool assembly can be securely attached to theplunger. Similarly, by rotating the plunger 16 in a second direction,the tool assembly 14 can be detached from the plunger.

The tool assembly 14 includes a drive shaft 102 having an end that isreceived within a mating receptacle 104 of the coupling 54 when the toolassembly is attached to the plunger 16, as shown in FIG. 1. Referring toFIG. 4, the receptacle 104 has an inner cylindrical sidewall portion 106that defines a chamber that is dimensioned and configured for receivinga mating end of the drive shaft 102 of the tool assembly 14. Thereceptacle 104 can have a rectangular, hexagonal, octagonal, or othergenerally cylindrical configuration capable of matingly receiving thedrive shaft 102 so as to so that the drive shaft rotates according torotation of the coupling 54.

With reference back to FIGS. 1 and 2, the magnetic preload provided bythe magnet 60 at the distal end 30 of the plunger 16 facilitates adesired connection, as the magnetic attraction helps urge the coupling54 onto the portion of the drive shaft 102 that protrudes into thecoupling chamber 66 through the respective apertures 62 and 64. Themating relationship between the receptacle 104 and the drive shaft 102thus enables the drive shaft to rotate commensurate with rotation of thedrive rod, as provided by the associated drive system 72. The receptacle104 can be integral with the coupling 54 or it could be mounted in acorresponding bore formed in the coupling or otherwise attached to thecoupling. Those skilled in the art will understand and appreciatevarious other connection arrangements between the drive shaft 102 andthe coupling 54 that can be employed to enable actuation of the toolassembly in response to rotation of the drive rod 46, all of which arecontemplated as falling with in the scope of the present invention.

In the particular example illustrated in FIGS. 1 and 2, the toolassembly 14 is in the form of a fluid dispensing system 110, such as canbe employed to dispense a desired amount of an adhesive material (e.g.,glue). The dispensing system 110 receives a desired fluid 112 to bedispensed via an input port 114, which can be in fluid communicationwith a source (not shown) of the fluid to be dispensed. For example, thesource of fluid can provide a pressurized source of fluid into thedispensing system 110 through an associated (flexible or rigid) conduit116 to facilitate its dispensing. By way of further illustration, thedispensing system can be employed to dispense a desired amount of anytype of fluid, such as a flux material for soldering, an oil material,grease or lubricants, chemical and pharmaceutical compounds, etc.

In order to dispense the fluid, the system further includes anArchimedes screw or other hydraulic or mechanical arrangement 118capable of dispensing a desired amount of fluid according to rotation ofthe drive shaft 102. For example, the Archimedes screw 118 includes anouter cylindrical member 120 that extends from a lower opening of thechamber to a location spaced apart from the opening, such as near theopposite end of the chamber near the plunger 16. The cylindrical member120 surrounds a threaded rod 122 that extends substantiallycoextensively within the cylinder. The conduit 116 is in fluidcommunication with cylindrical member 120 to provide the fluid 112 at adesired pressure so as to substantially fill the volume defined by themember. The diameter of the threads, which extend from a central shaftof the threaded rod 122, approximate the inner diameter of thecylindrical member 120. The threaded rod 122 can have any number ofturns suitable for dispensing a desired amount of fluid for apredetermined amount of rotation, such as to provide metered applicationof fluid. An end 124 of the threaded rod 122 is operatively coupled tothe drive shaft 102. In a particular aspect of the present invention,the threaded rod 122 can form a lower part of the drive shaft 102,although other mechanisms could be used to transfer movement of thedrive shaft to the threaded rod of the Archimedes screw 118.

In order to help maintain the fluid 112 within the cylindrical member120 of the Archimedes screw 118, a pair of seals 126 circumscribe thedrive shaft 102 at a location spaced from the end that is receivedwithin the receptacle 104 of the coupling 54. An annular shoulder 128,which is fixed about the drive shaft 102, extends radially outwardlyfrom the drive shaft and is interposed between the seals 126. Theengagement between the seals 126 and the shoulder 128 positions the endof the drive shaft 102 at a desired position relative to the coupling 54and provides a bushing that facilitates rotation of the drive shaft 102relative to the cylindrical member 120. The seals 126 and shoulder 128further help prevent fluid from traveling from within the Archimedesscrew 118 into the chamber 66. The seals 126 for example, are formed ofTeflon or another suitable material that will facilitate generally freerotation of the shoulder 128 relative to the seals and help keep thefluid within the Archimedes screw 118.

A nozzle 130 extends from the opening of the fluid dispensing system 112to direct the flow of fluid in a desired manner. In one aspect of thepresent invention (shown in FIG. 1), the nozzle 130 extends from thelower end of the chamber 112 at an acute angle relative to the actuatoraxis 32 to enable the fluid to be dispensed at a desired angle onto anassociated substrate (e.g., a printed circuit board). For example, itmay be desirable to dispense an adhesive fluid from the angled nozzle130, such as depending on the relative orientation of a component beingattached to a circuit board. Thus, the plunger 16 can be rotatedrelative to the housing 18 to appropriately position the nozzle 130 at adesired angular orientation relative to the work piece or substrate.Alternatively or additionally, the nozzle 130 might include a pluralityof different orifices (not shown) that can be selected for dispensingfluid depending on the particular application where the fluid is beingdispensed. The rotation of the plunger or another actuator further canbe implemented to index between different orifices associated with thenozzle 130.

By way of further illustration, FIG. 5 depicts another example of a toolsystem 200 in accordance with an aspect of the present invention. Thetool system includes a rotary-linear actuator 202 that is substantiallyidentical to the rotary-linear actuator drive system shown and describedwith respect to FIGS. 1 and 2. For purposes of brevity, a detaileddescription of the rotary-linear actuator 202 and its possibleimplementations has been omitted, as reference can be made back to thedescription of FIGS. 1 and 2 for additional information.

Briefly stated, the actuator 202 includes a plunger 204 that is moveablerelative to a housing 206 having spaced apart ends 208 and 210. Theplunger 204, which has spaced apart ends 212 and 214, can moverotationally about and/or linearly along an axis 216 that extendslongitudinally through the actuator 202. The rotary and/or linearmovement of the plunger 204 relative to the housing 206 is facilitatedby an arrangement of windings 218 and magnets 220, such as shown anddescribed herein. Appropriate bearings (low friction or air bearings) orother guide mechanisms (not shown) facilitate desired relative motionbetween the plunger 204 and housing 206.

In accordance with an aspect of the present invention, the system 200further includes an elongated drive rod 222 having end portions 224 and226 that are spaced apart from each other. For example, the drive rod222 extends substantially coaxially through the plunger 204 and thehousing 206. The drive rod 222 is mounted for substantially free axialmovement relative to the housing 206, such as commensurate with axialmovement of the plunger 204.

The distal end 226 of the drive rod 222 is connected to a coupling 228located near the distal end 214 of the plunger 204. The coupling 228 canbe at a generally fixed axial position relative to the plunger 204 or itcan be axially moveable with in a chamber 230 located near the end 214of the plunger. For example, the coupling 228 can be preloaded by amagnet 232 toward a rigid shelf or other support structure 234 locatedat the end 214 of the plunger 204. The coupling 228 further includes areceptacle 236 having a bearing or pivot element 237. The receptacle 236is dimensioned and configured for receiving a corresponding driveelement 238 of a tool assembly 239. The bearing 237 facilitatesalignment and receipt of the drive element 238. The coupling 228 thusrotates about the axis 216 according to rotation of the drive rod 222,which in turn causes corresponding rotation of the drive element 238received in the receptacle 236.

In the example of FIG. 5, a drive system 240 is operatively coupled torotate the drive rod 222 and associated coupling 228 about thelongitudinal axis 216. In this example, the drive system 240 isimplemented as a direct drive system, such as a servomotor or other typeof direct drive mechanism that transfers rotation force directly to thedrive rod 222. The direct drive system 240 can be mounted at theproximal end 208 of the housing, as shown in FIG. 5, such that the driverod 222 extends through a corresponding aperture 242 extending through arotor 244 of the drive system 240. The aperture 242 is dimensioned andconfigured to engage the drive rod 222 to rotate the drive rod about itsaxis commensurate with rotation of the rotor. Additionally, the driverod 222 can move axially substantially freely relative to the drivesystem 240, such as when the plunger 204 moves axially relative to thehousing 206.

The rotor 244, for example, includes a circular array of magnets 246 ofalternating polarity mounted around a central core 248 to provide forselected rotation relative to a stator 250 fixed relative to the housing206. The aperture 242 extends through the core 248. The stator 250includes windings 252 arranged in a generally circular array about therotor 244. The windings 252 are selectively energized to effect desiredrotation of the rotor 244 relative to the stator 250, which in turndrives the drive rod 222 about its axis. Those skilled in the art willunderstand various other types and configurations of direct drivesystems that could be employed to rotate the drive rod 222 in accordancewith an aspect of the present invention. Additionally, while the directdrive system 240 is illustrated as being mounted to the proximal end ofthe actuator housing, those skilled in the art will understand andappreciate that the drive system, alternatively, could be located withinthe interior the housing 206, such as near the proximal end 208 thereof.

In FIG. 5, the tool assembly 239 is illustrated in its detachedcondition relative to the plunger 204. That is, the tool assembly 239 isremovably connectable to the plunger 204 in accordance with an aspect ofthe present invention. For example, the tool assembly 239 has a threadedportion 254 that can be threaded to a corresponding threaded end portion256 of the plunger 204. The tool assembly 239 further includes a driveshaft 258 that extends axially from the proximal end of the toolassembly and terminating in the drive element 238 for receipt within thereceptacle 236 of the coupling. The drive element 238 and receptacle 236are dimensioned and configured to provide a desired mating connectiontherebetween, such that rotation of the coupling 228 results incorresponding rotation of the drive shaft 258, thereby actuating thetool assembly 239. Alternatively, the drive shaft 258 could beconfigured for mating connection with the receptacle 236 of the coupling228.

In the example of FIG. 5, a drill bit extends axially from a baseportion of the tool assembly 239. The drill is rotatable independentlyof rotation and axial movement of the plunger 204 relative to thehousing 206, such as in response to activation of the drive system 240.Those skilled in the art will understand and appreciate various othertypes of tool assemblies that could be utilized in conjunction with arotary-linear actuator tool system in accordance with an aspect of thepresent invention. Similar to the fluid dispensing system of FIG. 1,such other tools also can be configured for attachment to the distal endof the plunger, although different attachment mechanisms (permanent orremovable) also could be employed. For example, a pick-and-place system,which can include a clamp member activated by the drive system 240 and avacuum or suction member (coupled to a vacuum source) could be utilizedto grasp and hold items.

FIG. 6 illustrates an example of a functional block diagram of a system300 in accordance with an aspect of the present invention. The system300 includes a rotary-linear actuator 302 and a drive system 304. Thedrive system 304, for example, is operatively coupled to a drive rod,schematically illustrated at 306, which extends through at least aportion of the actuator 302 and operatively connected to an associatedtool system 307. One or more associated control systems 308 areoperative to control operation of the associated components of the toolsystem 300, including the rotary linear actuator 302 and/or the drivesystem 304. The drive system 304 also includes an encoder or resolver309 that provides position information to the control system 308indicative of the relative position of a rotor and stator of the drivesystem. The control system 308 thus controls operation of the drivesystem 304 in a desired manner based on the position information fromthe encoder 309.

By way of further example, the rotary-linear actuator 302 includesz-axis coils 310 and θ-axis coils 312, which are operative to providedesired linear and/or rotary movement of the actuator. The actuator 302also includes an encoder system 314, such as may include one or moreencoders, for sensing the relative position of the plunger and providingan encoder signal indicative of the sensed position. The encoder system314 may include an optical sensor in which the sensor detects markingsor other indicia located on and moveable with the plunger. It is to beunderstood and appreciated, however, that any type of encoding system(e.g., optical, magnetic, inductive, capacitive, etc.) could be utilizedin accordance with an aspect of the present invention.

The control system 308 can include a processor 316 coupled to memory318, which may be programmed and/or configured to control operation ofthe rotary-linear actuator in a desired manner as well as to control andsynchronize operation of the drive system 304 so that the associate toolsystem can interact with a work piece in a desired manner. The memory318 stores program code executed by the processor 316 for carrying outoperating functions of the system as described herein. The memory 318also serves as a storage medium for temporarily storing information suchas various sensed conditions of the module, an indication of the controlinformation implemented by the processor, and other data that may beemployed in carrying out the present invention.

The processor 316 is coupled to amplifier system 320, which may includeone or more amplifiers associated with the different sets of windings310, 312 in the actuator 302 as well as in the drive system 304. Theamplifier(s) 320, for example, can include switching networks forproviding a desired level of electrical current (e.g., bypulse-width-modulation or linear current control) to the coils and basedon control signals from the control system 308. The control system 308also is connected to the encoder system 314 for receiving positioninformation indicative of the position and/or movement of the plunger.The processor 316 thus controls the amplifiers to, in turn, controlenergization of each phase of the respective coils 310, 312 based on theposition information so as to effect desired movement of the plunger.The processor 316 also can control activation of the drive system 304 soas to effect desired rotation of the drive rod 306, which results indesired operation of the associated tool.

By way of example, the control information may be derived by using alook-up table having predetermined stored values or by calculation inaccordance with a desired control function. That is, executableinstructions and/or program data are stored in the memory 318 to defineoperating characteristics for the module. The control information isderived according to the program instructions executing at the processor316. Alternatively control instructions can be derived in real time byprocessing the sensed characteristics of the respective motive systemswith suitable control algorithms.

The system 300 further can include other sensors (e.g., current sensors,force sensors, etc. (not shown)) that provide corresponding feedbackinformation, based on which the processor may adjust the control signalsto the amplifier 320 to appropriately increase or decrease the amount ofcurrent being provided to selected parts of the system. In addition oralternatively, the executable instructions in memory may control themodule to implement a set of predefined movements with the rotary-linearactuator, such as may include a combination of rotational or linearmovements of the plunger along the respective Z and/or θ axes. Theparticular movements will vary as a function of the application in whichthe system is being utilized. The processor 316 may control eachamplifier independently or dependently according to the stored programinstructions.

By way of further example, if the tool system 307 is implemented as aglue dispensing system for gluing circuit components onto a printedcircuit board, the actuator can position the nozzle at a desiredposition relative to the board and rotate the plunger to orient thenozzle at desired angular orientation relative to the board, such asaccording to the type of component being attached and/or its orientationrelative to the circuit board. After the nozzle is appropriatelypositioned by activation of the Z and/or θ-axis coils 310 and 312, thedrive system 304 can be actuated to rotate the drive rod 306, such thata desired amount of glue is dispensed onto the circuit board. The toolsystem 300 and/or the board itself can then be moved (e.g., by single ormultiple axis linear motor system) and the nozzle repositioned fordispensing glue at the next position. This process, thus, can berepeated until all components have been appropriately attached to thecircuit board.

In view of the foregoing structural and functional features describedabove, the functionality of a tool system that may be implemented inaccordance with the present invention will be better appreciated withreference to FIG. 7. While, for purposes of simplicity of explanation,the methodology of FIG. 7 is shown and described as a flow diagramexecuting serially, it is to be understood and appreciated that thepresent invention is not limited by the illustrated order, as someaspects could, in accordance with the present invention, occur indifferent orders and/or concurrently with other aspects from that shownand described herein. Moreover, not all illustrated features may berequired to implement a methodology in accordance with an aspect thepresent invention.

The particular methodology may be implemented at a central motorcontroller, such as to control each motive device that forms part of atools system according to an aspect of the present invention. Themethodology begins at 350, such as in response to powering up the linearmotor system, in which variables and parameters are set to theirstarting values. Next, at 352, condition information, which can includeposition and/or movement data, is received for each of the motorsystems. For example, the condition information can include axial(Z-axis) and rotational (θ-axis) positions of a rotary-linear actuator,such as provided by one or more encoder systems operatively associatedwith the actuator. The position data also can include positioninformation of an associated drive system operative to control movementof a drive rod (or other type of drive component) that extends throughat least a substantial portion of the rotary-linear actuator. Examplesof encoders that could be utilized, in accordance with an aspect of thepresent invention, include magnetic encoders, inductive encoders,capacitive encoders, and/or optical encoders. Such encoders may providetheir position data via a physical communications link and/or a wirelesscommunications link employing a known communications protocol. From 352,the methodology proceeds to 354.

At 354, energization requirements are determined for each of the motivedevices based on the condition information as well as other data. Theother data, for example, provides an indication of conditions associatedwith an environment and/or process in which the tool system is beingimplemented. The determination of how to energize the associated motivedevices, for example, can be made by a microprocessor programmed and/orconfigured with a look-up table that provides a current or voltagecommand signal as a function of position data and condition data.Alternatively or additionally, motor control algorithms may beimplemented to calculate control requirements, such as may include themagnitude and direction of electric current that should be applied towhich winding(s) to effect a desired axial and/or rotary movement of theactuator. After the control requirements have been determined, themethodology proceeds to 356.

At 356, the control instructions are provided to energize selectedwindings. For example, the control instructions are provided to one ormore amplifiers that selectively activate (358) desired windings of therotary-linear actuator. The electrical energy provided to the actuatormotors results in desired rotary and/or linear movement of a moveableplunger portion of the actuator. Next at 360, a determination is made asto whether the plunger has been moved to a desired position, which caninclude axial and rotational positions. The axial and rotationalpositions of the plunger can be extrapolated to determine the positionand orientation of the tool assembly attached to the plunger. If thedetermination is negative, indicating that the plunger is not at adesired relative position, the methodology returns to 352, in whichcondition information is received, such as based on position and othercharacteristics that are sensed. The condition information is then usedto control operation of the rotary-linear actuator, as described above.Appropriate feedback, such as from sensed conditions, can be used tofurther adjust operating parameters of the system. Once the plunger isdetermined to be at a desired position, the drive motor is energized soas to activate the associated tool assembly (362) by moving the driverod that extends through the rotary-linear actuator, such as to performa desired operation on a work piece or other item.

By way of example, the tool assembly can include a glue dispensingsystem, a pick and place system, a rotational tool (e.g., drill, screwdriver, wrench) or other appliance for which it may be desirable toposition with substantially high accuracy relative to a work piece oritem. The drive motor can be activated to perform a desired operation,such as based on feedback which indicates progress of the operation andwhen the operation is complete. Alternatively, the drive motor can beactivated to rotate an associated drive rod a desired amount, such as toa predetermined operation. After the

The foregoing example can be repeated to implement desired operationswith the associated tool assembly, such as part of a manufacturingprocess.

What has been described above includes exemplary implementations of thepresent invention. It is, of course, not possible to describe everyconceivable combination of components or methodologies for purposes ofdescribing the present invention, but one of ordinary skill in the artwill recognize that many further combinations and permutations of thepresent invention are possible. Accordingly, the present invention isintended to embrace all such alterations, modifications and variationsthat fall within the spirit and scope of the appended claims.

What is claimed is:
 1. An actuator system for a tool, comprising: arotary-linear actuator comprising: a housing; and an elongated plungermounted within the housing for rotary and linear movement relative to acentral axis extending longitudinally through the plunger; and anelongated drive rod that extends within at least a portion of the rotarylinear actuator substantially parallel to the central axis, the driverod being operatively associated with the plunger for linear movementsubstantially commensurate with the linear movement of the plunger andfor permitting substantially independent rotary movement of the driverod relative to the plunger.
 2. The system of claim 1, furthercomprising a coupling located near a distal end portion of the plunger,the drive rod being operatively connected to the coupling, such that thedrive rod and the coupling move together.
 3. The system of claim 2,further comprising at least one preloading element that urges thecoupling toward the distal end of the plunger so that the coupling moveslinearly with the linear movement of the plunger.
 4. The system of claim3, the at least one preloading element comprising at least one magnetlocated between the coupling and the distal end of the plunger so as toattract the coupling toward the distal end of the plunger.
 5. The systemof claim 1, further comprising a drive system operatively coupled to thedrive rod to effect rotation of the drive rod about a central axisthereof substantially independently of rotary movement of the plunger.6. The system of claim 5, the drive rod further comprising a proximalend spaced apart from a distal end that is operatively coupled to theplunger, a portion of the drive rod traverses through a proximal endportion of the rotary linear actuator as the plunger experiences thelinear movement, the drive system engaging the proximal end portion ofthe drive rod to effect rotation of the drive rod relative to theplunger.
 7. The system of claim 6, the drive rod further including aplurality of ribs or notches that extend along at least the proximalportion of the drive rod.
 8. The system of claim 1, further comprising atool assembly connected at a distal end of the plunger, the toolassembly being operatively coupled to the drive rod so that rotation ofthe drive rod actuates the tool assembly.
 9. The system of claim 8, thetool assembly being removably connected to the distal end of theplunger.
 10. The system of claim 9, each of the tool assembly and distalend of the plunger including mating threaded portions to removablyconnect the tool assembly to the distal end of the plunger.
 11. Thesystem of claim 8, further comprising a coupling located at a distal endof the plunger and connected with the drive rod, the coupling beingoperative to transfer rotation of the drive rod to the tool assembly.12. The system of claim 11, further comprising at least one preloadingelement that urges the coupling toward the distal end of the plunger sothat the coupling and drive rod move linearly with the linear movementof the plunger.
 13. The system of claim 12, the at least one preloadingelement further comprising at least one magnet fixed at an axiallocation between the coupling and the distal end of the plunger so as toattract the coupling toward the distal end of the plunger.
 14. Thesystem of claim 12, further comprising a drive system operativelycoupled to the drive rod to effect rotation of the drive rod andcoupling about a longitudinal axis extending through the drive rodindependently of the rotary movement of the plunger.
 15. The system ofclaim 8, the tool assembly further comprising a dispenser having anozzle, the dispenser dispensing fluid through the nozzle in response torotation of the drive rod.
 16. Thee system of claim 15, the nozzle beingoriented at an acute angle relative to the central axis so that therotary movement of the plunger relative to the housing results incorresponding rotation of the nozzle, whereby application of the fluidin a desired direction is facilitated.
 17. A tool system, comprising: anouter housing having a generally cylindrical sidewall portion; anelongated plunger mounted for rotary and linear movement within thehousing relative to a central axis extending longitudinally through theplunger; an elongated drive rod that extends through at least a portionof the housing and is operatively connected for substantially linearmovement of the plunger, the drive rod also being capable ofsubstantially independent rotation relative to rotary movement of theplunger; and a tool assembly connected at a distal end of the plunger,the tool assembly being operatively associated with the drive rod sothat the independent rotation of the drive rod actuates the toolassembly.
 18. The system of claim 17, the tool assembly being removablyconnected at the distal end of the plunger.
 19. The system of claim 18,each of the tool assembly and the distal end of the plunger includingmating threaded portions operative to removably connect the toolassembly to the distal end of the plunger.
 20. The system of claim 17,further comprising a coupling connected with the drive rod near thedistal end of the plunger, the coupling being operative to transfer theindependent rotation of the drive rod to the tool assembly.
 21. Thesystem of claim 20, further comprising at least one preloading elementthat urges the coupling toward the distal end of the plunger so that thecoupling and drive rod move linearly with the linear movement of theplunger.
 22. The system of claim 17, further comprising a drive systemoperatively coupled to the drive rod to effect the independent rotationof the drive rod about a longitudinal axis extending through the driverod.
 23. The system of claim 22, the tool assembly further comprising afluid dispenser operative to dispense fluid through a nozzle in responseto the independent rotation of the drive rod, the nozzle being locatedat a distal end of the tool assembly generally aligned with the centralaxis.
 24. The system of claim 23, the fluid being an adhesive material.25. A method for controlling a tool system, the tool system including arotary-linear actuator that provides linear and rotary movement of aplunger relative to a housing and a drive rod that moves linearly withplunger and is capable of rotating independently relative to theplunger, the method comprising: adjusting at least one of rotary andlinear position of the plunger; and after the plunger is at a desiredposition, rotating the drive rod independently of plunger so as toactivate an associated tool.
 26. The method of claim 25, the rotatingfurther comprising activating a drive system operatively coupled to thedrive rod to rotate the drive rod a desired amount relative to theplunger.
 27. The method of claim 25, further comprising dispensing adesired amount of fluid in response to rotation of the drive rod.